Deploying Webapps with Docker

Great! So you have now looked at docker container run, played with a Docker container, and also got the hang of some terminology. Armed with all this knowledge, you are now ready to get to the real stuff — create Docker Images, and deploy these images as web applications with Docker.

Task 1: Run a static website in a container

Note: Code for this section is in this repo in the static-site directory.

First, we’ll use Docker to run a static website in a container. The website is based on an existing image. We’ll pull a Docker image from Docker Hub, run the container, and see how easy it is to set up a web server.

The image that you are going to use is a single-page website that was already created for this demo and is available on the Docker Hub as dockersamples/static-site.

Run the image directly in one go using docker run as follows.
```
$ docker container run --detach dockersamples/static-site
```
Note: The current version of this image doesn’t run without the -d flag. The -d flag enables detached mode, which detaches the running container from the terminal/shell and returns your prompt after the container starts. We are debugging the problem with this image but for now, use -d even for this first example.

So, what happens when you run this command?

Since the image doesn’t exist on your Docker host, the Docker daemon first fetches it from the registry and then runs it as a container.

Now that the server is running, do you see the website? What port is it running on? And more importantly, how do you access the container directly from our host machine?

Actually, you probably won’t be able to answer any of these questions yet! ☺ In this case, the client didn’t tell the Docker Engine to publish any of the ports, so you need to re-run the docker run command to add this instruction.

Let’s re-run the command with some new flags to publish ports and pass your name to the container to customize the message displayed. We’ll use the -d option again to run the container in detached mode.

Stop the container that you have just launched. In order to do this, we need the container ID.

Since we ran the container in detached mode, we don’t have to launch another terminal to do this. Run docker container ps to view the running containers.

$ docker container ps
CONTAINER ID        IMAGE                  COMMAND                  CREATED             STATUS              PORTS               NAMES
a7a0e504ca3e        dockersamples/static-site   "/bin/sh -c 'cd /usr/"   28 seconds ago      Up 26 seconds       80/tcp, 443/tcp     stupefied_mahavira

Check out the CONTAINER ID column. You will need to use this CONTAINER ID value, a long sequence of characters, to identify the container you want to stop, and then to remove it. The example below provides the CONTAINER ID on our system; you should use the value that you see in your terminal.
```
$ docker container stop a7a0e504ca3e
$ docker container rm   a7a0e504ca3e
```
Note: A cool feature is that you do not need to specify the entire CONTAINER ID. You can just specify a few starting characters and if it is unique among all the containers that you have launched, the Docker client will intelligently pick it up.
Launch a container in detached mode as shown below: The command summary the above command:
- --detach will create a container with the process detached from our terminal
- -publish-all will publish all the exposed container ports to random ports on the Docker host
- --env is how you pass environment variables to the container
- --name allows you to specify a container name
- AUTHOR is the environment variable name and Your Name is the value that you can pass
```
$ docker container run --name static-site --env AUTHOR="Your Name" --detach --publish-all dockersamples/static-site
e61d12292d69556eabe2a44c16cbd54486b2527e2ce4f95438e504afb7b02810
```
Now you can see the ports by running the docker port command with the name of the newly created container static-site.
```
$ docker port static-site
443/tcp -> 0.0.0.0:32772
80/tcp -> 0.0.0.0:32773
```
Note: If you are running Docker Desktop for Mac, Docker Desktop for Windows, or Docker Desktop on Linux, you can open http://0.0.0.0:[YOUR_PORT_FOR 80/tcp]. For our example this is http://localhost:32773.
You can also run a second webserver at the same time, this time specifying a custom host port mapping to the container’s webserver. Be sure to change the name
```
$ docker container run --name static-site-2 --env AUTHOR="Your Name" --detach --publish 8888:80 dockersamples/static-site
```
Open your browser to http://0.0.0.0:32773 and open a second tab http://0.0.0.0:8888. We can now view both websites running in parallel on your Docker Host.

--publish will publish instruct the container to map the specified container port to the host port. 8888:80 = Host:Container Port

Now that you’ve seen how to run a webserver inside a Docker container, how do you create your own Docker image? This is the question we’ll explore in the next section.

Stop and remove the containers since we won’t be using them anymore.

$ docker container stop static-site
$ docker container rm static-site

Let’s use a shortcut to remove the second site:
```
$ docker container rm -f static-site-2 static-site-3
```
Note: rm -f is the not nice way of removing containers. Be warned

Run docker container ps -a to make sure the containers are gone.

$ docker container ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

Next Step

For the next step in the tutorial, head over to Docker Images and Volumes